The invention relates in general to reducing the core temperature of human beings and in particular to lightweight, portable, non-powered apparatus and methods for reducing the core temperature of human beings.
Humans engage in physical activities including, for example, workplace operations, exercises, athletic competition and training, emergency rescue operations, and military combat and training. Risks associated with physical activities, particularly physical activities in a hot environment, are heat illness and heat stroke. Exertional heat stroke (EHS) may result when a human engages in strenuous physical activity for a prolonged period of time in a hot environment or when metabolic heat production is sufficiently elevated above resting.
Lowering the human body's elevated core temperature can reduce the risk of EHS. Various methods are known for lowering the body's core temperature. Cooling suits of various types are known. Cooling suits often interfere with the wearer's activity, add additional work burden to the wearer, and are expensive. Cooling suits are practical for some specialized activities, but are not a broadly applicable way of lowering body core temperature in physically active individuals. For large numbers of individuals, for example, soldiers in a training environment or team athletes, methods of avoiding heat stress have included ingesting substantial amounts of water, frequent rest periods, moving the individuals to a shady area, loosening or removing clothing, spraying the individuals with water misters, changing the time of day of training, and changing the order of training events. Nevertheless, decreased performance due to heat stress continues. As stated by R. O'Hara et al. (Current and Future Cooling Technologies Used in Preventing Heat Illness and Improving Work Capacity for Battlefield Soldiers: Review of the Literature, Military Medicine, Volume 173, Number 7, pp. 653-657, July 2008): “Currently, practical cooling devices that provide sustained cooling effects for battlefield soldiers are not available.” (p. 653); and: “Clearly, there is a need for effective portable methods of cooling.” (p. 655).